The invention generally relates to remote controls with security features which prevent false activation and, in particular, an infrared remote control employing alternating codes for controlling a microsurgical system.
Present day ophthalmic microsurgical systems provide one or more surgical instruments connected to a control console. The instruments are often electrically or pneumatically operated and the control console provides electrical or fluid pressure control signals for operating the instruments. The control console usually includes several different types of human actuable controllers for generating the control signals supplied to the surgical instruments. Often, the surgeon uses a foot pedal controller to remotely control the surgical instruments.
The conventional console has push-button switches and adjustable knobs for setting the desired operating characteristics of the system. The conventional control system usually serves several different functions. For example, the typical ophthalmic microsurgical system has anterior and/or posterior segment capabilities and may include a variety of functions, such as irrigation/aspiration, vitrectomy, microscissor cutting, fiber optic illumination, and fragmentation/emulsification.
While conventional microsurgical systems and ophthalmic systems have helped to make microsurgery and ophthalmic surgery possible, these systems are not without drawbacks. Microsurgical and ophthalmic systems are relatively costly and are often purchased by hospitals and clinics for sharing among many surgeons with different specialties. In eye surgery, for example, some surgeons may specialize in anterior segment procedures, while other surgeons may specialize in posterior segment procedures. Due to differences in these procedures, the control system will not be set up with the same operating characteristics for both procedures. Also, due to the delicate nature of eye surgery, the response characteristics or "feel" of the system can be a concern to surgeons who practice in several different hospitals, using different makes and models of equipment.
U.S. Pat. Nos. 4,933,843, 5,157,603, 5,417,246 and 5,455,766, all of which are commonly assigned and the entire disclosures of which are incorporated herein by reference, disclose improved microsurgical control systems. For example, such systems provide improved uniformity of performance characteristics, while at the same time providing enough flexibility in the system to accommodate a variety of different procedures. The systems shown in these patents improve upon the prior art by providing a programmable and universal microsurgical control system, which can be readily programmed to perform a variety of different surgical procedures and which may be programmed to provide the response characteristics which any given surgeon may require. The control system is preprogrammed to perform a variety of different functions to provide a variety of different procedures. These preprogrammed functions can be selected by pressing front panel buttons.
In addition to the preprogrammed functions, these patents disclose providing each surgeon with a programming key, which includes a digital memory circuit loaded with particular response characteristic parameters and particular surgical procedure parameters selected by that surgeon. By inserting the key into the system console jack, the system is automatically set up to respond in a familiar way to each surgeon.
For maximum versatility, the console push buttons and potentiometer knobs are programmable. Their functions and response characteristics can be changed to suit the surgeons' needs. An electronic display screen on the console displays the current function of each programmable button and knob as well as other pertinent information. The display screen is self-illuminating so that it can be read easily in darkened operating rooms.
Although the above-described systems provide improvements over the prior art, further improvements are needed to improve performance, simplify operation, simplify repair and replacement, reduce the time and cost of repairs, and so forth.
Medical sites such as operating rooms, out-patient surgery rooms, procedure rooms and clinics commonly have electronic equipment such as television monitors, video cassette recorders and stereos, each of which has its own infrared remote control to allow convenient control of their operation. These medical sites may also have microsurgical or other medical systems, such as ophthalmic machines, which also employ infrared remote controls so that a doctor or surgeon can remotely control the machine's operation. It is common for the electronic equipment to use standard commercial encoding formats, such as a Manchester encoded data stream, to transmit code so that, for instance, a single remote control might be used for several different systems by changing the code transmitted. However, there is no consensus which constrains certain codes to certain systems or classes of systems, and manufacturers are free to choose any code, at their discretion. It is imperative that remote controls for medical systems use adequate security techniques to ensure that operation of one of the remote controls for electronic equipment do not cause inadvertent actuation or deactivation of some medical system function, nor any change in control setting of a particular function of the medical system.
Many prior art medical systems have employed proprietary or complicated encoding schemes to avoid false activation. However, such schemes are expensive to develop and implement and cannot be implemented with off-the-shelf remote control IR encoding ICs.
Other prior art medical systems have used extended codes, such as 32 bit or longer codes, to minimize the possibility of two systems using the same code. However, such extended codes reduce battery life in the remote because of the extended transmission time required and there is no guarantee that a particular code will be unique.